press_home

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full behavioral burden, and it discloses almost nothing: not whether the device must be connected or unlocked, what happens to the current app/foreground state, or whether the action is reversible. It only restates the action.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One short, front-loaded sentence with no filler or redundancy. It is efficient, though its brevity comes at the cost of useful detail rather than through disciplined editing.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained. However, for a device-control action with zero annotation coverage and an undocumented `serial` parameter, the description is thinner than the tool's invocation context warrants.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% for the single optional `serial` parameter, and the description never mentions it. An agent cannot learn from either source that `serial` selects which device receives the key press or what the default (null) resolves to.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (press) and resource (HOME button), which is unambiguous on its own. It does not, however, differentiate itself from the sibling navigation buttons (press_back, press_recents, press_power, press_enter) or state what HOME does on the device.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no when-to-use guidance, no mention of prerequisites (e.g. a connected/awake device), and no reference to the alternative navigation tools. The agent must infer the use case purely from the tool name.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.